X-ray tube and apparatus



May 1 8, 1943 E. SCHIEBOLD 2,319,350 X-RAY TUBE AND APPARATUS 2 sheets-sheet 1 INVE/V TOR:

Filed Dec. 31, 1940 Patented May is, 1943 UNITED STATES PATENT OFFICE X-RAY TUBE AND APPARATUS Ernst Schiebold, Leipzig, Germany; vested in the Alien Property Custodian Application December 31, 1940, Serial No. 372,606 In Germany June 14, 1937 16 Claims.

centration and a focussing of X-rays upon a limited area or point.

The subject matter hereof is a continuation in part of my United States patent application Serial No. 260,818 filed on March 9, 1939, for Testing materials by X-rays, which has become Patent No. 2,259,708.

In accordance with the invention of the said patent application materials are tested and their characteristics are determined by irradiating a limited area of said material by X-rays striking such area in various, predetermined directions, or at various, predetermined angles, and the secondary radiation produced by the X-ray on said area of the material projects ontofla suitable light sensitive means. The record thus produced may be interpreted and tabulated for the purposeof determining a number of characteristics of the material, such as its molecular structure, internal stresses, etc. "larly intelligible and informative secondaryradi- The irradiation yields a particuation, if it extends as a continuous sheet, e. g. along the surface of a cone, the irradiated material being placed at the apex of the cone. In

sources of X-ray and the materials to be tested.

This invention istherefore to provide for 'X-ray means capable of performing the type of irradiation just described.

It is another object of this invention to provide for recording means, which temporarily or permanently register the secondary radiation, showing its direction and distribution, and rendering it available for study and interpretation,

' In one embodiment of this invention an X-ray tube yielding an X-ray pencil may be moved relatively to the material to be tested and a camera in such fashion, that the pencil describes the surface of the cone, remaining focussed at all times on a limited area of the material to be cathode.

tested. Instead of obtaining this efiect by means of moving parts, this invention provides also a special X-ray tube, in which the bundled electronic discharge of a central cathode is directed by suitable means, for instance a rotating electromagnetic field, onto the suitable inclined surface of an annular cathode, and the X-rays pencils consecutively emanating from points along a circle upon the annular anti-cathode, over which sweeps the primary pencil or bundle of electrons, produce a conical sheet of X-rays, at the focus of which the material to be testedis placed.

If we omit the electromagnetic field simultaneous irradiation might be produced with such an X-ray tube instead of the said X-ray irradiation. Or a similar result is obtained, if the cathode as well as the anti-cathode are annular, and the conical X-ray sheet is again produced in one.

The invention provides also for a particular shaping of the X-ray tube or its envelope, for instance as an annulus or hollow cone, so that the recording means, such as a camera, and possibly also the material to be tested, may be allocated upon the inside of sucha hollow structure.

The invention further touches upon the cooling and other particular problems arising with devices thereof, the objects and advantages of which will be discussed hereinafter in detail, in connection with the views of the drawings. Such description and views are however to be interpreted as illustrations of the invention only, and not in limitation thereof.

In the drawings:

Fig. 1 is a vertical cross-section of an X-ray tube and camera adapted for simultaneous conical irradiation.

Fig. 2 shows, in a similar view, a detailof a modified X-ray tube, which embodies a vertical X-ray pencil in addition to conical irradiation. Fig.3 shows a partly schematic elevational view of an arrangement of devices, where an .X-ray pencil is to be moved relatively to the material to be tested.

Fig. 4 is a diagrammatic elevational view of another embodiment in which a rotating magnetic field guides the electron pencil flowing from a solid central cathode to an annular antiof theX-ray tube may be executed in metal in which case the anti-cathode 3 may form part of said enclosure 5. According to X-ray practice the envelope may be highly evacuated. The enclosure 5 may comprise a cooling chamber 24, through which a cooling fluid may be passed by way of the inlet and outlet 4. A conical section 6 of said cooling chamber 2 may extend up into the X-ray tube, thus providing, as a reentering portion, a conical recess in the bottom of the tube. The double Wall of the conical section 6 may be provided with registering endless windows which are suited for the passage of X-rays issuing from the anti-cathode 3. A pair of concentric conical sheets 8 serves as a lens conducting the radiated X-ray through windows I and a film onto a focal area or point I 2 of the material 9 to be tested. Photosensitive material, e. g. film H is mounted in a suitable camera or upon the innermost conical surface of the section 6, Which faces the outside of the X-ray tube, so that it intercepts the rays of interference reflected at the focal point I2, The glow cathode 2 may be mounted in the X-ray tube by a support, which serves at the same time .to connect it to a suitable source of current.

Or, as exemplarily shown in the drawing, the connector l6, which is mounted upon the envelope of the X-ray tube but suitably insulated 1 relatively to the enclosure 5, may provide a high negative potential for the glow cathode 2 by way of wiring 25. Wiring 25 is accommodated in an insulated system comprising the central tube l3 and branch tubes Hl, l5, these tubes being preferably fixedly allocated in the envelope by way of brackets 26 and 21. Annulus H, which closes the cooling chamber 24 relatively to the interior of the X-ray tube and carries the anticathode 3, is connected to the positive terminal of the high tension supply and is preferably grounded at iii. In order to facilitate an exchange .of the anti-cathode, for substituting an anti-cathode at different angle for instance, the X-ray tube may be executed in sections, which may be taken apart, and in that case a connector IQ for connection with a vacuum manifold may be provided for.

The conical camera recess serving to receive a conically disposed film may also be shaped to accommodate films or light sensitive means of different shape, e. g. the steps of cylindrical film 28 of Fig. 3. The glow cathode may be replaced by a cathode adapted for ionic actuation. Or the annular anti-cathode 3 may be irradiated by a cathode, say pencil, which is directed centrally down in the tube, but which is magnetically redirected onto the annular anticathode, by way of a moving electro-magnetic field for instance.

If a central X-ray pencil is to be provided for, in addition to conical irradiation, the junction point of tubes l3, Id and l5 and the apex of the double walls of the conical section 6 may be reorganized, whereas all other parts of an X-ray tube of Fig. 1 may remain the same. A detail of the reorganized parts is shown in Fig. 2. A glow cathode 23 depends below the tube 13, and registers with the anti-cathode 2|, which is connected, by way of a suitable cooling manifold extension 29 with the positive terminal of a high tension source of current, e. g. to section 6 of metal chamber 24. By way of suitable windows 22 and lens 23 the central X-ray pencil emanating from the anti-cathode 2| is then trained upon the focal area l2 below. The cooling chamber 24 may be suitably partitioned in order to provide for the proper conduction of the cooling fluid to and away from anti-cathode 2|, as taught by the prior art.

The additional central X-ray pencil normally striking the focal area l2 from the anti-cathode 2| may serve for the purpose of establishing a delimiting curve in addition to a curve of that nature provided by the conical radiation discussed before. I

When a device of Fig. 1 is used, and we do not have at our disposal the central X-ray pencil which is obtained by way of a device of Fig. 2, then a second delimiting curve (circle) may be produced by the conical radiation by way of interference on a test body, e. g. a gold foil or a film of powder of gold M, mounted, e. g. applied with a brush, upon the surface of the material to be tested.

The embodiment of Fig. 4 generally corresponds to that of Fig. 1, except that a more conventional cathode 2, which is centrally disposed in the tube above the indentation accommodating a light sensitive indicating means such as a film, takes the place of the annular cathode 2 surrounding the central conical indentation 6 in the embodiment of Fig. l.

The electrons emitted by the annular cathode 2 of Fig. 4 may be magnetically directed, as a beam, onto any particular point of the anticathode 3. In the manner known in the art of electronics such a diverted beam of an electron may be oscillated to sweep over the anti-cathode 3, e. g. by a rotating magnetic field set up by a suitable coil in the manner corresponding the way in which a polyphase current sets up an outer rotating field in a polyphase induction motor. When the deflected, oscillating electron beam sweeps over the anti-cathode, X-rays issue from the anti-cathode 3 of Fig. 4, and form a conical sheet of X-rays describing a solid angle of almost 180 and focussed on the material to be tested which is deposited centrally upon a preferably fiat support for the envelope 5 of the X-ray tube of Fig. 4.

When standard X ray tubes are to be used instead of the special embodiments of Figs. 1, 2 or 3 for carrying out the methods of the instant invention one or more standard X-ray tubes are revolved about an axis normal to the surface of the material to be tested, the primary X-ray pencil passing successively through all azimuths; but the film remains stationary relatively to the material to be tested. This embodiment of the invention may, of course, be also carried out in connection with one or more stationary X-ray tubes, by rotating the material to be tested together with the camera, as illustrated in Fig. 3. A piece of material 9 to be tested is deposited upon the turntable 3|. Turntable 3|, and a motor 32 slowly rotating said turntable by way of a worm drive 33, are mounted upon a vertical slide 34. The slide 34 is accommodated upon the riser 36 and may be vertically adjusted thereupon by a feed screw and wheel 35.

By way of vertical adjustment of turntable 3| the surface 31 of material 9 may be placed into the focal range of X-ray pencil 38 of X-ray tube 39, i. e. into alignment with or slightly above the crossing point of said pencil 38 with the axis of rotation of the turntable at which a normal and central pencil it} of a second X-ray tube 4| may also be arranged to play. By way of a bracket 42 supporting X-ray tube 39 the latter may be adjusted in an are upon a circular extension 43 extending up from riser 33. One or more cylindrical film sections 28 may preferably .be' centralized upon the surface 31 of the material 9, e. g. in step cone fashion. Upon rotation of the properly adjusted turntable 3| the X'-ray pencil 38 will establish a conical sheet of irradiation having an apex upon a focal area upon the surface 3'! of material 9, in accordance with the principal featureof this invention.

The circular extension 43 may be graduatedas shown, one or more of the spaces marked on by the scale corresponding for instance to the thickness of the conical sheet of X-rays produced by X-ray pencil 38. With the help of the graduation of the circular extension 43 we may therefore shift the X-ray tube 39 for the distance corresponding to the thickness of the X-ray pencil 38. If such shifting is brought about time and time again during theoperation of the apparatus, e. g. "after each revolution of the turntable 3 l, the X-ray pencil 38: will scan a space many times the thickness of the conical'sheet first circumscribed. The focal point on the material to be tested will therefore be irradiated by X-ray filling a solid cone subtehded'by a zone, the width of the zone corresponding to the thickness of the pencil 38 multiplied by the number of times the X-ray tube 39 has been shifted along the circular extension 43. By irradiating an area of the material to be tested in the manner just described,

we obtain another photograph defining the crys tal lattice of the material tested. By continuing to shift the X-ray tube 39 along the circular extension 43, until the subtending zone becomes a'segment, we can irradiate the area to be tested throughout a solid cone of irradiation, which yields another type of photograph for the inter pretation of the crystal lattice.

The. method. disclosed herein for measuring 'crystals'tructure and tension may also be applied for evaluation of a three-dimensional state of forces in the interior for a material to be tested,

up to a limited depth below the surface of said material. For this purpose the conical sheet of X-rays is focussed upon underlying levels of material, and reasonable deductions may be yet I do not wish to be limited thereby, except as the state of the art and the appended claims may require, for it is obvious that various modifications and changes may be made in themethod and form of embodiment of my invention, without departing from the spirit and. scope thereof.

What I claim is:- i

1. An apparatus for testing material, comprising a hollow, substantially conical camera means adapted to accommodate a light sensitive film substantially in the formation of a cone, a support adapted to accommodate said camera means in an inverted position and the material to be tested below the apex of said means so that the material is positioned substantially inside of, and upon the axis of the cone formed by a film accommodated by said camera, and a source of X-rays having an anti-cathode and mounted above said support in a position in which said anti-cathode is spaced relatively to said axis and X-rays issuing therefrom strike the material to be tested at a predetermined inclination to said axis, so that a secondary radiation which may be caused to issue from the material by the X-rays strikingthe material will irradiate a film accommodated in said camera means.

2. An apparatus for testing material, comprising a hollow camera means adapted to accommodate'a light sensitive film substantially in the "formation of a cone. a support adapted to'accommodate the material to be tested and said camera means in a position in which the material is located in the solid angle of, and upon "the axisof the cone formed by a film accom- .modated by said camera means, and a source of -X-rays having an anti-cathode mounted close to said support but removed from said axis so that X-rays issuing therefrom strike the material to'betest'ed at a large acute angle of inclination'to said axis, said angle of inclination being preserved when said source and support .are relatively rotated around said axis, so that a secondary radiation which may be caused to issue from the material by the X-rays striking the material will arradiate a film accommodated in said camera means.

3. An apparatus for testing material, comprising a substantially conical camera means adapted to accommodate a light sensitive film substantially in the formation .of a cone, a support adapted to accommodate the material to be tested and said means above the material in the inverted position in which-the material is positioned substantially inside of, and upon the axis of the cone formed by a film accommodated by said means, a source-of X-rays trained to play an X-ray pencil onto the material to be tested in the direction of said axis, and a. source of X-rays having an anti-cathode mounted close to said support at a point removed from said axis and directed so that X-rays issuing therefrom strike the material to be tested at a large acute angle of inclination to said axis, and so that a second- -ary radiation which may be caused to issue from the material by the X-rays striking the material will irradiate a film accommodated in said camera means.

4. An apparatus for testing material, comprising a camera means adapted to accommodate a the material to be tested in line with and in the direction of said axis from above such cone, and at a predeterminedangle of inclination to said axis substantially underneath such cone,.respec .tively. i

5. An apparatus for testing materials, comprising a support for said material, an X-ray tube mounted to train a pencil of rays onto a limited area of a surface of material on said support at an incline to said surface, and a mechanism for relatively rotating said support and said tube in respect to an axis passing substantially normal to the surface of said support through such a limited area.

6. In apparatus for testing materials, an X-ray tube for irradiating a material from all sides and comprising an envelope, a cathode and an annular anti-cathode concentrical and operatively registering with each other in said envelope, said envelope having a reentrant double wall which serves as a cooling jacket and is substantially concentrical with and extends through said anticathode.

7. In apparatus for testing materials, an X- ray tube for irradiating material from a plurality of sides and comprising an envelope, a cathode and an annular anti-cathode concentrical and :op'eratively registering with each other in said envelope, said envelope being conically reentrant in concentricity with said cathode and extending into said anti-cathode.

8. In apparatus for testing materials, an X- ray tube for irradiating material from a plurality of sides and comprising an envelope having an indentation, a cathode and an annular anticathode fixedly mounted in said envelope, said anti-cathode encircling said indentation, the electronic discharge of said cathode being directed onto said anti-cathode, and said anticathode yielding X-rays passing through said indentation and converging onto a central focal point at which the material to be tested is to be placed.

9. In apparatus for testing materials, an X- ray tube for irradiating material from a plurality of sides and comprising an envelope having an indentation, an annular cathode and an annular anti-cathode concentrical and operatively registering with each other in said envelope, and a window on said envelope facussing a zone on said indentation for passing a conical sheet of X-rays from said anti-cathode to the outside of said envelope onto the material to be tested.

10. In apparatus for testing materials, an X- ray tube for irradiating material from a plurality of sides and comprising an envelope, an annular cathode and an annular anti-cathode concentrical and operatively registering with each other in said envelope, and a Window on said envelope for passing a conical sheet of X-rays from said anti-cathode to the outside of said envelope onto the material to be tested, said envelope having a reentrant portion arising substantially centrally inside of said anti-cathode into said cathode.

11. In apparatus for testing materials, an X- ray tube for irradiating material from a plurality of sides and comprising an envelope, an annular cathode and an annular anti-cathode concentrical and operatively registering with each other in said envelope, and a window on said envelope for passing a conical sheet of X-rays from said anti-cathode to the outside of said envelope onto the material to be tested, said envelope having a reentrant conical portion spacedly surrounded by and arising substantially centrally inside of said anti-cathode and serving as a camera accommodating a conical X-ray sensitive film.

12. In apparatus for testing materials, an X- ray tube for irradiating material to be tested from a plurality of sides comprising an envelope, an annular cathode and an annular anti-cathode concentrical and operativelyregistering witheach other in said envelope, a central window on said envelope for passing an X-ray pencil, an annular window on said envelope for passing a conical sheet of X-rays from said anti-cathode to the outside of said envelope, and another cathode and another anti-cathode registering with each other in said envelope and adapted to yield an X-ray pencil passing through said central window, so that a material to be tested may be irradiated at one point but at different angles, through said window.

13. In apparatus for testing materials, an X- ray tube for irradiating material to be tested from a plurality of sides comprising an envelope, a cathode and an annular anti-cathode fixedly mounted in said envelope, the electronic discharge. of said cathode being directed onto said anti-cathode, and said anti-cathode yielding X- rays converging at a solid angle of almost 180 onto a central focal point at which the material to be tested is to be placed, and a circumferential compartment formed in said envelope and serving to receive a cooling fluid.

14. In an apparatus for testing materials, an X- ray tube comprising an envelope, a cathode, and an annular anti-cathode inclined .to yield X-rays converging at a focal point, said envelope having a recess extending into said anti-cathode, and said envelope being shaped so that such X-rays focally converge upon a sample of material centrally located upon a level surface, upon which said envelope is deposited.

15. In an apparatus for testing materials, an X-ray tube comprising an envelope, a cathode, an annular anti-cathode inclined to yield X-rays converging at a focal point, electromagnetic means directing electrons emitted by said cathode as a pencil onto said anti-cathode and oscillating such electron pencil so that it sweeps over the annular extent of said anti-cathode, said envelope having a recess extending into said anticathode.

16. Anapparatus for testing materials, comprising a turntable for supporting the material to be tested, a support for an X-ray tube, means for adjusting said support and turntable at an incline with respect to each other and bring into intersection the axis of rotation of the turntable with the X-ray pencil of the tube, whereby the azimuth of the pencil is adjustable relatively to the axis of rotation of the turntable so that the X-ray pencil may establish a conical sheet of irradiation having an apex upon a limited focal area of a surface of the material.

ERNST SCHIEBOLD. 

